Use a soft-bristle brush or cloth to gently scrub the interior of the base. Sprinkle the cloth with more baking soda if there are stuck-on particles. Pour out the water, add some cool water to rinse, ...
If your car feels down on power, a trip to the garage might be in order, but checking these things before you go could save you a pile of cash.
Choose a dry day, clear the floor, tackle rust and oil stains, then scrub and pressure wash with a mild cleaner to strip away ...